title: Change of cardiac reserve during abnormal pregnancy and its evaluation.
abstract: OBJECTIVE
  To investigate the change of cardiac reserve during abnormal pregnancy and explore its evaluation methods.
  
  
  METHODS
  Totally 96 women with abnormal pregnancies (AP group), 356 women with normal pregnancies (NP group), and 100 women of childbearing age (CBA group) were monitored by the exercise cardiac contractility monitor (ECCM). Phonocardiogram of participants at resting status was recorded by ECCM. The amplitude of first heart sound (S1), the amplitude of second heart sound (S2), cardiac cycle, diastolic duration (D), and systolic duration (S) were detected and then the S1/S2 ratio,the D/S ratio, and heart rate (HR) were calculated.
  
  
  RESULTS
  Compared with the CBA group, S1/S2 ratio and HR were significantly higher and D/S was significantly lower in both AP group and NP group (all P<0.001). Compared with the NP group, S1/S2 ratio and HR were significantly higher in AP group and D/S was significnatly lower (all P<0.001). A D/S ratio less than 1.1 or S1/S2 ratio higher than 1.8 was associated with higher risk of poor pregnancy outcomes. Among four common pregnancy-associated abnormalities, the level of cardiac reserve was lowest in eclampsia, followed by twins, gestational diabetes mellitus, and gestational hypertension.
  
  
  CONCLUSIONS
  Cardiac reserve is mobilized during pregnancy, and is especially during the abnormal pregnancies due to the heavy cardiac burden. S1/S2 ratio, D/S ratio, and HR are useful in evaluating the cardiac reserve during abnormal pregnancy.
authors.affiliation: Chongqing Engineering Research Center for Medical Electronics Technology, College of Bioengineering,Chongqing University, Chongqing 400030. China. guoxm@cqu.edu.cn
authors.forename: Guo
authors.initials: G
authors.lastname: Xing-ming
authors.forename: Zhong
authors.initials: Z
authors.lastname: Li-sha
authors.forename: Wang
authors.initials: W
authors.lastname: Dong
authors.forename: You
authors.initials: Y
authors.lastname: Feng-zhi
authors.forename: Xiao
authors.initials: X
authors.lastname: Shou-zhong
mesh_terms: D000328:Adult; D005260:Female; D006321:Heart / Q000503:physiopathology*; D006801:Humans; D010701:Phonocardiography; D011247:Pregnancy; D011248:Pregnancy Complications / Q000503:physiopathology*; D011256:Pregnancy Outcome; D055815:Young Adult